Co基Heusler铁磁薄膜/窄禁带半导体异质结自旋泵浦效应的超快磁光光谱研究

基于对低功耗、高速度、高密度集成磁电子器件的迫切需求，利用纯自旋流实现磁矩操控与翻转是当前自旋电子学的研究焦点，而铁磁薄膜与强自旋−轨道耦合材料异质结的高效自旋−电荷互转换和相关物理是其核心研究内容。作为实现向半导体中自旋注入的核心材料，铁磁薄膜/半导体异质结中自旋泵浦效应的研究报道还很少。基于自旋泵浦效应的自旋注入不受铁磁体与半导体阻抗失配问题的困扰，可为实现向半导体的高效自旋注入提供更为有效的物理实现方案。本项目拟在优化Co基Heusler铁磁薄膜与窄禁带半导体异质结及其界面设计基础上，利用时间分辨磁光克尔技术对其自旋泵浦效应开展系统研究，确定Heusler薄膜与不同窄禁带半导体异质结界面的自旋混合电导、自旋透明度等界面自旋输运参数并厘清不同物理机制对其界面自旋输运的影响。本项目对提高Heusler铁磁薄膜磁电耦合器件性能、实现向半导体中的高效自旋注入具有重要基础物理研究意义。

Aiming for developing the low-power, high-speed, high-integration magnetoelectronic devices, magnetization manipulation and magnetic switching based on the spin current has become the core topics in the research community of spintronics, where the high-efficient conversion between the charge and spin current and the associated physics, based on the heterostructures composed of ferromagnetic films and materials with strong spin-orbit coupling, is the key issue to be focused onto. As the core material in the spin injection into semiconductors, the ferromagnetic film/semiconductor heterostructures have gained little attention on its spin pumping effect. While the spin injection based on spin pumping can overcome the problem of large impedance mismatch between ferromagnets and semiconductors, therefore provides extremely effective physical scheme for high-efficient spin injection into semiconductors. This project will focus on the systematic spin pumping effect investigation by utilizing the time-resolved magneto-optical Kerr effect technique, with optimal design of the Co-based Heusler ferromagnetic film/narrow-gap semiconductor heterostructures and the respective interfaces. The key interfacial spin transport parameters such as the spin-mixing conductance, spin transparency so on will be determined, and the associated essential physical mechanisms that contribute or influence the interfacial spin transport property will be explored and understood. This project is both fundamentally and technically important in terms of realizing the high-efficient spin injection into semiconductors, and improving the Heusler alloy-based magnetoelectronic devices.